Floppy Plants

My last blog entry lamented about the cold, wet summer of 2009, in which many plants grew so tall from all the moisture that they fell right over, creating a huge mess in many of our gardens…

Large plantings of Bee Balm and Obedient Plant on the pond banks collapsed in a tangle, their flowers smothered. So much for my lush summer pondside color display and all that nectar for the Ruby-throated Hummingbirds!  And there is nothing more sad than beautiful peonies flattened by heavy rain. Looking on the bright side, my husband (who has a hidden talent in flower arranging!) tells me that the longer stems were great for big flower vases. But what can a gardener do about floppy plants?

It’s OK to pinch plants!
Staking plants is definitely an option, but somehow that seems like too much work to me. Not to mention, the plants still might flop over. Gardener’s Supply sells plastic stem supports (kind of like horticultural girdles) which seem to work, but they are expensive for those on a budget. Next year, I plan to pre-emptively prune some of the worst offenders on this summer’s flop list. In late spring, after the plants have emerged and are between 4-8″ tall, shear or pinch their stems closer to the the ground, leaving some foliage intact to help the plant rebound quickly. Each stem then sprouts multiple stems from from where it was cut, resulting in slightly smaller (but more numerous) flowers and sturdier stems less likely to fall over later in the year.

Below: the flowering stems of Sedum (Autumn Stonecrop) toppled over:

IMG_1603-1Below: Sedum when grown in half-decent soil with some moisture, benefits from an early season stem pinching to keep the plant stems from toppling from the sheer weight of its blooms.Autumn Stonecrop is a late-season pollinator magnet, and as long as it gets some sun, will grow in most New England garden soils. It usually needs no pruning at all in poor,dry soils, making it a good low-maintenance choice for a dry roadside planting or an area with hot blazing sun.

sedum-drivewayYou might be asking yourself, why pinch plants back if the aim is to have a natural garden? Plants growing in the wild seem to stay upright without any help from us. But take a look an old field blooming with wild flowers and notice how dense the vegetation is. There’s no room for flopping, because the crowd of plants hold each other up. And chances are, the soil in that old field is not as rich as your typical garden bed, so plants do not grow as tall. So if you are trying to achieve a meadow effect of your own, plant the area as thickly as you can to allow plants to support themselves on their own. And don’t over-fertilize. A little compost on occasion is all a natural-style garden should ever need to keep itself thriving.

Plants suitable for pinching to control height:

The following plants will grow sturdier, more heavily branched stems  (and more flowers!)  if you cut their stems back early in the season:

New England Aster
New York Aster
Tall Sedum varieties (Autumn Joy, Blackjack, etc)
Bee Balm
Ironweed
Coneflower
Eupatorium
Helianthus
Goldenrod
Heliopsis
Boltonia
Helenium
Leucanthemum
Chrysanthemum
Dendranthema
Lobelia
Hibiscus
Obedient Plant (Physostegia virginiana)

Some plants, such as peonies, are just not suitable for cutting back to prevent collapse. Your only option for the larger flowering peonies is to either situate them where their heavy flowers can cascade freely over the edge of a wall during bloom time, or stake the stems and keep the plants rigid using peony rings. Horticulturalist and plant author Tracy DiSibato-Aust also suggests removing the first terminal flower bud on peonies to prevent the weight of the large first flower from pulling the remaining plant down.

In a large scale landscape design, pinching back your plants is probably too labor-intensive, but for most of us with smaller garden areas or vignettes of natural habitat, pinching plants can keep a habitat garden tidier and more manicured, something your neighbors might appreciate if you live in the ‘burbs.

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